This invention relates to joints, specifically to a joint using a combination of hydraulics and ball bearings to convert linear motion into radial motion and thereby provide both variable extension assist, as well as an infinite number of flexion stops for controlled flexion flow. Applications may include, but are not limited to, joints for orthotic devices which facilitate the extension and flexion of a human joint, such as a knee. The compact configuration of the present invention would provide the cosmetic advantage of allowing such orthotic devices to fit more easily under clothing wherein they would be less noticeable during use.